Quarterly Financial Data (Unaudited) (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Millions	2 Months Ended	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Oct. 31, 2016	Sep. 30, 2016	Jul. 31, 2016	Jun. 30, 2016	Apr. 30, 2016	Mar. 31, 2016	Jan. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Oct. 31, 2016	Dec. 31, 2015	Oct. 31, 2015
Quarterly Financial Information Disclosure [Line Items]
Operating revenues		$ 5,799	$ 6,482	$ 5,555	$ 5,729	$ 5,577		$ 6,576		$ 5,213		$ 5,377		$ 23,565	$ 22,743		$ 22,371
Operating income (loss)		1,262	1,695	1,387	1,437	888		1,954		1,259		1,240		5,781	5,341		5,078
Income (loss) from continuing operations		705	957	691	717	376		1,001		624		577		3,070	2,578		2,654
Income (Loss) From Discontinued Operations, net of tax		(2)	(2)	(2)		(598)		180		(112)		122		(6)	(408)		177
Net income (loss)		703	955	689	717	(222)		1,181		512		699		3,064	2,170		2,831
Net Income (Loss) Attributable to Parent		$ 703	$ 954	$ 686	$ 716	$ (227)		$ 1,176		$ 509		$ 694		$ 3,059	$ 2,152		$ 2,816
Income (loss) from continuing operations attributable to Duke Energy Corporation common shareholders [Abstract]
Basic		$ 1.00	$ 1.36	$ 0.98	$ 1.02	$ 0.53		$ 1.44		$ 0.90		$ 0.83		$ 4.37	$ 3.71		$ 3.80
Diluted		1.00	1.36	0.98	1.02	0.53		1.44		0.90		0.83		4.37	3.71		3.80
Income (loss) from discontinued operations attributable to Duke Energy Corporation common shareholders [Abstract]
Basic						(0.86)		0.26		(0.16)		0.18		(0.01)	(0.60)		0.25
Diluted						(0.86)		0.26		(0.16)		0.18		(0.01)	(0.60)		0.25
Net income attributable to Duke Energy Corporation common shareholders [Abstract]
Basic		1.00	1.36	0.98	1.02	(0.33)		1.70		0.74		1.01		4.36	3.11		4.05
Diluted		$ 1.00	$ 1.36	$ 0.98	$ 1.02	$ (0.33)		$ 1.70		$ 0.74		$ 1.01		$ 4.36	$ 3.11		$ 4.05
Duke Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues		$ 1,721	$ 2,136	$ 1,729	$ 1,716	$ 1,681		$ 2,226		$ 1,675		$ 1,740		$ 7,302	$ 7,322		$ 7,229
Operating income (loss)		403	777	485	484	302		815		464		481		2,149	2,062		1,960
Net Income (Loss) Attributable to Parent		205	466	273	270	140		494		261		271		1,214	1,166		1,081
Progress Energy [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues		2,348	2,864	2,392	2,179	2,208		2,965		2,348		2,332		9,783	9,853		10,277
Operating income (loss)		493	657	591	487	292		814		560		475		2,228	2,141		2,160
Income (loss) from continuing operations						104		449		274		212		1,268	1,039		1,065
Income (Loss) From Discontinued Operations, net of tax															2		(3)
Net income (loss)		447	343	277	201	106		449		274		212		1,268	1,041		1,062
Net Income (Loss) Attributable to Parent		444	341	274	199	104		446		272		209		1,258	1,031		1,051
Duke Energy Progress [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues		1,251	1,460	1,199	1,219	1,174		1,583		1,213		1,307		5,129	5,277		5,290
Operating income (loss)		256	411	282	286	135		438		255		258		1,235	1,086		1,024
Net Income (Loss) Attributable to Parent		168	246	154	147	60		271		131		137		715	599		566
Duke Energy Florida [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues		1,095	1,401	1,191	959	1,030		1,381		1,133		1,024		4,646	4,568		4,977
Operating income (loss)		234	240	306	196	155		373		300		213		976	1,041		1,115
Net Income (Loss) Attributable to Parent		344	120	158	90	64		206		171		110		712	551		599
Duke Energy Ohio [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues		497	471	437	518	511		489		428		516		1,923	1,944		1,905
Operating income (loss)		76	102	65	83	90		106		55		96		326	347		303
Income (loss) from continuing operations														193	192		149
Income (Loss) From Discontinued Operations, net of tax			(1)					34				2		(1)	36		23
Net Income (Loss) Attributable to Parent		65	55	30	42	57		89		23		59		192	228		172
Duke Energy Indiana [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues		745	802	742	758	733		809		702		714		3,047	2,958		2,890
Operating income (loss)		170	230	210	186	176		239		174		176		796	765		644
Net Income (Loss) Attributable to Parent		36	121	106	91	$ 72		$ 129		$ 85		$ 95		354	$ 381		$ 316
Piedmont Natural Gas [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	$ 322	444	183	201	500		$ 172		$ 160		$ 353		$ 464	1,328		$ 1,149		$ 1,383
Operating income (loss)	96	115	(4)	5	170		(50)				104		171	286		225		263
Net Income (Loss) Attributable to Parent	$ 54	$ 63	$ (11)	$ (8)	$ 95		$ 39		$ (7)		$ 63		$ 98	$ 139		$ 193		$ 137